On April 18, 2026 Moderna, Inc. (NASDAQ:MRNA) reported that the Company will present data from a Phase 1/2 study of mRNA-4359, an investigational cancer antigen therapy, at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting in San Diego, CA, on April 17-22, 2026. The presentation reports safety, efficacy and translational data from a Phase 2 dose-expansion cohort of the Phase 1/2 study (NCT05533697), which evaluated mRNA-4359 + pembrolizumab as a first-line therapy in patients with locally advanced or metastatic melanoma.

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Among 12 participants, mRNA-4359 + pembrolizumab resulted in an overall response rate (ORR) of 83% (95% CI: 52%-98%), with two patients achieving a complete response and eight achieving a partial response, as well as a disease control rate (DCR) of 92% (95% CI: 62%-100%). The median time to response was six weeks (range, 5.6-24.0). Responses occurred across baseline tumor PD-L1 expression categories, with an ORR of 88% (95%CI: 47%-100%) among patients with PD-L1+ (TPS≥1%) tumors, and 67% (95%CI: 9%-99%) among patients with PD-L1- (TPS<1%) tumors. Consistent with mRNA-4359’s mechanistic rationale, antigen-specific T-cell responses and novel expanded T-cell receptor (TCR) clonality was observed in all patients (n=7) with evaluable samples. mRNA-4359 + pembrolizumab demonstrated a manageable safety profile, with no new immune-related adverse events (AEs).

"This study evaluating mRNA-4359 + pembrolizumab as a first-line treatment option reflects our ambition to demonstrate the potential of mRNA technology throughout a cancer patient’s journey. While conducted among a small patient population, we are encouraged by the high response rates and mechanistic translational results," said David Berman, M.D., Ph.D., Chief Development Officer of Moderna. "We look forward to further evaluating the potential of mRNA-4359 in patients with melanoma."

"This early data supports the potential activity of the mRNA-4359 + pembrolizumab combination, with promising anti-tumor activity," Dr. Pavlina Spiliopoulou, School of Cancer Sciences, University of Glasgow, the abstract’s lead author and presenter. "The consistent activation of antigen-specific T-cell responses provides important early evidence that mRNA technology could be used to help direct the immune system against melanoma in a multi-targeted manner."

This presentation builds on promising early data presented at the 2025 European Society for Medical Oncology Congress, in which mRNA-4359 + pembrolizumab achieved an ORR of 24% and DCR of 60% among 29 evaluable patients with checkpoint inhibitor-resistant/refractory (CPI-R/R) melanoma. Among those with response-evaluable disease and PD-L1+ (TPS≥1%) tumors, the ORR was 67%.

The U.S. FDA has granted Fast Track designation for mRNA-4359 in combination with pembrolizumab for the treatment of CPI refractory unresectable or metastatic melanoma with PD-L1+ (TPS>1%). Fast Track is designed to facilitate the development and expedite the review of therapies and vaccines for serious conditions and that fill an unmet medical need. Programs with Fast Track designation may benefit from early and frequent communication with the FDA, in addition to a rolling submission of the marketing application.

The details of the presentation are as follows:

Abstract Presentation #CT106: First-Line mRNA-4359 Plus Pembrolizumab (Pembro) in Locally Advanced or Metastatic Melanoma: Results from the Phase 1/2 mRNA-4359-P101 Study

Session Title: Clinical Trials Plenary 3: Cellular Therapies and Complex Immunotherapies

Session Date/Time: Monday, April 20, 10:15AM – 12:15PM PT

Presenter: Dr. Pavlina Spiliopoulou, School of Cancer Sciences, University of Glasgow, UK

About mRNA-4359

mRNA-4359 is an investigational, immune-evasion targeted cancer antigen therapy that encodes broad epitopes of PD-L1 and IDO1. With its dual mechanism of action, it is designed to elicit antigen-specific T-cell responses to simultaneously: (1) kill tumor cells expressing PD-L1 and IDO1, and (2) deplete immunosuppressive cells that shield the tumor from attack. This is hypothesized to rebalance the tumor microenvironment into an immune-permissive state, supporting sustained and durable anti-tumor activity with a manageable safety profile.

(Press release, Moderna Therapeutics, APR 18, 2026, https://feeds.issuerdirect.com/news-release.html?newsid=8054079664924385&symbol=MRNA [SID1234664479])

On April 18, 2026 Pliant Therapeutics, Inc. (Nasdaq: PLRX) reported the presentation of updated data from its Phase 1 trial of PLN-101095, in combination with pembrolizumab, in patients with immune checkpoint inhibitor (ICI)-refractory advanced or metastatic solid tumors. The oral presentation was made at the Clinical Trials Mini Symposium of the American Association for Cancer Research (AACR) (Free AACR Whitepaper) 2026 Annual Meeting.

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Timothy A. Yap, MBBS, Ph.D., Medical Oncologist and Physician-Scientist at the University of Texas MD Anderson Cancer Center, presented results from the dose escalation portion of the ongoing Phase 1a/1b trial covering data as of February 27, 2026. Results showed that in the heavily pretreated ICI-secondary refractory patient subgroup, twice daily (BID) treatment with PLN-101095 at the highest doses in combination with the ICI pembrolizumab showed antitumor activity. One confirmed overall complete response, two confirmed overall partial responses, including one patient with a complete response of baseline target lesions, and one unconfirmed partial response were reported in patients with cholangiocarcinoma, non-small cell lung cancer (NSCLC), melanoma and head and neck squamous cell carcinoma, respectively. As of the data cutoff date, the median time on treatment for the three confirmed responders was 19 months, who experienced an average baseline target tumor reduction of 89%.

All responding patients showed large increases (4- to 13-fold vs. baseline) in plasma interferon gamma (IFN-γ) after a 14-day run-in period of monotherapy with PLN-101095. At Week 10, all responders maintained more than a 2-fold increase in IFN-γ. No non-responders showed meaningful increases in IFN- γ. In addition to IFN- γ increases, all responding patients showed elevated plasma PD-L1 levels, known to be induced by increased IFN-γ and a predictor of an improved ICI response. As increases in IFN-γ have the potential to serve as a biomarker of TGF-β inhibition and an early indicator of PLN-101095 anti-tumor activity. Pliant anticipates further study of this biomarker as part of the expansion cohorts in the Phase 1b trial.

PLN-101095 was generally well tolerated across all doses evaluated with few discontinuations (n=2) due to adverse events. Rash was the most common treatment-related adverse event (TRAE), all Grade 1 or 2, and the majority of events occurred within the first 2 days of the initial pembrolizumab dose. One Grade 3 TRAE was observed.

PLN-101095 demonstrated a dose-ordered exposure at Day 14 with doses ≥1000 mg BID achieving sustained IC90 coverage and all participants dosed at ≥1000 mg BID maintaining IC75 coverage over 24 hours. These results support the consistent target engagement of PLN-101095.

Sixteen patients with ten different tumor types, including both primary and secondary refractory patients, were enrolled in five dose cohorts. Patients were treated for 14 days with PLN-101095 monotherapy administered orally at doses of 250 mg twice a day (BID) (n=1), 500 mg BID (n=2), 1000 mg BID (n=6), 1000 mg three times a day (TID) (n=4) or 2000 mg BID (n=3), followed by the addition of pembrolizumab at 200 mg administered intravenously every three weeks until disease progression. Scans were conducted at baseline, Day 14, Week 10, and every 8 weeks thereafter.

Dr. Yap commented "One of the ways that the tumor microenvironment can suppress responses to immune checkpoint inhibitors is through a process that is activated by integrins to upregulate TGF-β. PLN-101095 is designed to inhibit the integrins before they can ever do that, which gives it significant potential to stimulate or reinvigorate the immune response to cancer. These clinical trial data, for the combination of PLN-101095 and pembrolizumab in patients with secondary immune checkpoint inhibitor resistance, show the potential to meet a high unmet therapeutic need."

"These encouraging results show a deepening of baseline tumor reductions in confirmed responders and an increased median time on treatment with PLN-101095 in patients with difficult-to-treat ICI refractory tumors," said Bernard Coulie, M.D., PhD., Chief Executive Officer of Pliant. "We have initiated the Phase 1b trial to expand this novel combination therapy in specific tumor types to address patients in need and deliver value to our investors."

Slides accompanying these data can be found here and under the Investors & Media page of Pliant’s website at www.PliantRx.com.

PLN-101095 Phase 1b Indication Expansion Trial

Pliant has initiated a Phase 1b open-label indication expansion trial enrolling three cohorts of patients with NSCLC, tumors with high tumor mutational burden or clear cell renal cell carcinoma. Patients will be treated for 14 days with PLN-101095 dosed at 1,000 mg twice daily as monotherapy, after which pembrolizumab will be added as combination therapy. Enrollment is underway with interim data expected in 2027.

PLN-101095 for the Treatment of Checkpoint Resistant Tumors

PLN-101095 is an oral, small molecule inhibitor of integrins αvβ8 and αvβ1. PLN-101095 is being evaluated in Phase 1a/1b open-label, dose-escalation and indication expansion trial to evaluate the safety, tolerability, pharmacokinetics, and preliminary evidence of antitumor activity of PLN-101095 in combination with pembrolizumab, in patients with immune checkpoint inhibitor (ICI)-refractory advanced or metastatic solid tumors. Activated transforming growth factor-β (TGF-β) has been shown to foster an immuno-suppressive tumor microenvironment (TME) that contributes to immune-checkpoint inhibitor (ICI) resistance and treatment failure in cancer.1 Blocking integrins αvβ8 and αvβ1 has been shown to prevent the activation of TGF-β and is expected to stimulate immune activation by increasing immune cell infiltration into the tumor microenvironment.2,3 PLN-101095 in combination with an anti-PD-1 monoclonal antibody (mAb) elicited a dose-dependent reduction in tumor volume and increased CD8+ T cell tumor infiltration in the tumor microenvironment compared with anti-PD-1 mAb therapy alone.4 In preclinical studies, PLN-101095 demonstrated monotherapy activity in reduction of tumor volume and increased cluster of differentiation (CD)8+ T cell infiltration.

(Press release, Pliant Therapeutics, APR 18, 2026, View Source [SID1234664529])

On April 17, 2026 Cogent Biosciences, Inc. (Nasdaq: COGT), a biotechnology company focused on developing precision therapies for genetically defined diseases, reported that preclinical data from the Company’s KRAS and ErbB2 pipeline programs will be presented during poster sessions at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026 taking place in April 17-22 in San Diego, CA.

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"As we prepare for the potential launch of bezuclastinib later this year, we are excited to share updates from two of our pipeline programs this weekend at the 2026 annual AACR (Free AACR Whitepaper) meeting," said Andrew Robbins, Cogent’s President and Chief Executive Officer. "First, we are presenting data on CGT1263, our novel pan-KRAS(ON) inhibitor, which shows best-in-class cellular potency along with evidence that its kinase selectivity advantage over multi-RAS inhibitors could drive clinical differentiation with regards to skin toxicity, a current liability of advanced clinical programs. Separately, we provide an update on CGT4255, our novel, selective ErbB2 inhibitor that was specifically designed for its best-in-class CNS penetrant properties to address a significant unmet need for HER2+ patients with brain metastases. This presentation also includes preclinical data in combination with a HER2 ADC suggesting potential synergistic activity leading to improved duration of therapy as well as re-sensitization of patients following HER2 ADC resistance. With multiple potential blockbuster programs advancing in our pipeline, we believe these new data underscore the long-term potential of Cogent Biosciences."

Poster Details

Title: Characterization of CGT1263, a KRAS (ON/OFF) inhibitor clinical candidate with selectivity for mutant KRAS over HRAS and NRAS
Session Category: Experimental and Molecular Therapeutics
Session Title: Novel Antitumor Agents 1
Session Date and Time: April 19, 2026 – 2:00 PM – 5:00 PM PT (5:00 PM – 8:00 PM ET)
Location: Poster Section 17
Poster Board Number: 13
Poster Number: 410

Mutations in KRAS are among the most prevalent mutations found in cancer, occurring most often in colorectal cancer, non-small cell lung cancer and pancreatic cancer. The preclinical poster highlights Cogent’s internally developed pan-KRAS(ON) inhibitor with >500x selectivity for KRAS over HRAS and NRAS. Plasma exposure following oral administration across species resulted in sustained pERK inhibition and robust antitumor activity. Tumor pERK inhibition was also achieved with limited skin suppression, supporting the potential of a larger therapeutic window for CGT1263 when compared to multi-RAS inhibitors currently in clinical development. This aligns with historical data implicating the RAS-MAPK-ERK pathway as essential for skin development given its role in regulation of keratinocyte proliferation, differentiation, and survival; combined suppression of multiple targets within this pathway is thought to be the driver of frequent rash observed in patients treated with multi-RAS inhibitors. Overall, these findings suggest CGT1263 could provide an advantage for patients, enabling higher dosing designed to elicit a more profound molecular response. Investigational New Drug (IND) enabling studies are ongoing with an IND submission expected later this year.

Title: Preclinical characterization of CGT4255, an EGFR sparing, pan-mutant HER2 clinical development candidate with potential best-in-class brain penetration
Session Category: Experimental and Molecular Therapeutics
Session Title: Tyrosine Kinase, Phosphatase, and Other Inhibitors
Session Date and Time: April 21, 2026 – 2:00 PM – 5:00 PM PT (5:00 PM – 8:00 PM ET)
Location: Poster Section 18
Poster Board Number: 7
Poster Number: 5869

Cogent’s EGFR-sparing, brain-penetrant ErbB2 inhibitor includes potent coverage of key mutations (YVMA, S310F, V842I, L755S) inadequately addressed by currently approved therapies. Activating mutations in the ErbB2 gene have been identified in multiple cancers and demonstrate a tumorigenic role similar to that of ErbB2 amplification. New data presented describe CGT4255’s >100-fold selectivity over EGFR while robustly engaging HER2 amplification, insertion and mutant lines in addition to reinforcing best-in-class potential CNS performance relative to other agents in development. Additional mechanistic studies presented suggest CGT4255 may have synergistic effects on efficacy and durability when combined with HER2 targeted ADCs. Preclinical evidence demonstrates that concurrent treatment of CGT4255 and T-DXd enhances receptor internalization and cancer cell apoptosis, suggesting the potential for a synergistic combination that could improve patient outcomes. The Phase 1 study of CGT4255 is ongoing.

Posters will be available on the ‘Posters and Publications’ page of Cogent’s website.

(Press release, Cogent Biosciences, APR 17, 2026, View Source [SID1234664468])

On April 17, 2026 Nested Therapeutics, a clinical-stage oncology company developing transformative therapies for RAS/MAPK-driven disorders, reported initial clinical results from its ongoing Phase 1 study evaluating NST-628, a brain-penetrant non-degrading pan-RAF/MEK molecular glue, in patients with advanced solid tumors. Data presented at the AACR (Free AACR Whitepaper) Annual Meeting 2026 demonstrate encouraging single-agent anti-tumor activity and a favorable tolerability profile in a range of RAF and RAS-mutant tumors, including a 38% response rate and 85% disease control rate at the recommended dose in heavily pretreated NRAS and BRAF Class II/III melanoma, a population that represents approximately 33% of cutaneous melanoma patients, for whom no approved targeted therapies are available.

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"These initial data support our hypothesis that targeting RAF/MEK signaling with a single-agent, fully brain-penetrant pan-RAF/MEK molecular glue can deliver meaningful clinical benefit with a tolerability profile that supports sustained dosing even in comparison to what may be expected from combination regimens," said Darrin Miles, Chief Executive Officer of Nested Therapeutics. "We are particularly encouraged by the durable responses in NRAS and BRAF Class II/III melanoma – large patient populations with historically poorer outcomes and for whom there are no approved targeted therapy options – as well as early signals of clinical activity beyond melanoma, including in KRAS-mutant solid tumors and evidence of brain penetrance. Together, these clinical findings, in addition to robust preclinical evidence and favorable drug properties, support the potential for NST-628 to address significant unmet need across RAS/MAPK-driven cancers and to serve as a foundational therapy in both monotherapy and combination settings."

Key Data Highlights

As of the data cutoff date of February 1, 2026, NST-628 has been administered to 69 patients: 64 patients in dose-escalation and 5 patients in the expansion phase. Key findings are summarized below.

Monotherapy Clinical Activity in evaluable patients (with at least one tumor assessment or who discontinued the study) at Recommended Dose for Expansion (RDE)

NST-628 monotherapy demonstrated a 38% response rate in BRAF Class II/III and NRAS-mutant melanoma (N=13) and 33% response rate overall (N=18); response rates include one unconfirmed partial response
Disease control rate was 85% in the melanoma subgroup and 72% overall
With a median follow-up of 6.4 months, the median duration of response in melanoma was not yet reached
Anti-Tumor Activity Beyond Melanoma

Responses to NST-628 were observed across multiple tumor types and genotypes, including KRAS-mutant ovarian and cervical cancers – highlighted by an ongoing partial response in a KRAS G12V-mutant cervical cancer patient with a treatment duration exceeding one year – as well as NRAS/BRAF Class III-mutant colorectal cancer and BRAF Class II-mutant thymic cancer
A patient with high-grade astrocytoma (BRAF V600E), previously treated with multiple lines of RAF/MEK-targeted therapy, demonstrated 70% tumor shrinkage on NST-628 monotherapy, consistent with NST-628’s preclinical brain penetration profile
Reductions in ctDNA correlated with radiographic response
Safety and Tolerability

Adverse events were consistent with the mechanism of action and predominantly Grade 1-2
Most common treatment-related adverse events included dermatologic, gastrointestinal, CK elevation, constitutional, and ocular events
Grade ≥3 TRAEs were infrequent; most common was CK elevation
No Grade 5 events reported
At the RDE:
Discontinuation rate: 9%
Dose intensity (actual dose delivered vs. intended): 82%
"The anti-tumor activity observed with NST-628 monotherapy is encouraging," said Philip Komarnitsky, MD, PhD, Chief Medical Officer of Nested Therapeutics. "A safety profile that supports continuous dosing at 82% dose intensity with a 9% discontinuation rate, combined with the response rate of 38% and disease control rate of 85% in NRAS and BRAF Class II/III melanoma patients at the recommended dose, is promising for this patient population with no approved targeted therapies. The clinical evidence of activity in malignancies with BRAF class III mutations, an emerging resistance mechanism to RAS inhibitors, and of brain penetrance consistent with preclinical findings is particularly noteworthy. These data support the continued development of NST-628 as monotherapy and its evaluation in rational combinations."

Nested plans to continue enrollment in the ongoing Phase 1 expansion cohort and evaluate NST-628 in additional malignant and non-malignant MAPK-driven diseases and combination settings, including mutant-selective RAS and other inhibitors.

Poster Presentation Details

Title: Preliminary results from a Phase 1a/b dose-escalation and expansion trial of the pan-RAF-MEK molecular glue NST-628 in patients (pts) with advanced or refractory RAF, KRAS, and NRAS-mutant solid tumors

Presenter: Ahmad A. Tarhini, MD, PhD, Moffitt Cancer Center

Presentation Date and Time: Monday, April 20, 2026, 2:00 PM-5:00 PM PT

Session: PO.CT01.01 – Phase 0 and First-in-Human Phase I Clinical Trials

Location: Section 51

About the Phase 1 Study of NST-628, NST-628-001

The ongoing Phase 1 open-label, single-arm, two-part study (NCT06326411) is investigating the safety, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of single-agent NST-628 in adult patients with RAS-MAPK pathway mutated/dependent advanced solid tumors, especially diverse KRAS, NRAS, and BRAF alterations, who have exhausted standard treatment options. The study includes two parts: dose escalation (Part A), which enrolled 64 patients across seven dose regimens, followed by dose expansion (Part B) at the recommended dose for expansion. Part B is currently enrolling. For more information, visit clinicaltrials.gov.

About NST-628

NST-628 is a brain-penetrant, non-degrading molecular glue designed to inhibit RAF and MEK signaling by stabilizing RAF-MEK complexes in a catalytically inactive form. This mechanism is intended to prevent pathway reactivation, a common liability of existing RAS/MAPK-targeted therapies, and enable more durable pathway suppression across RAS/MAPK-driven cancers.

(Press release, Nested Therapeutics, APR 17, 2026, View Source [SID1234664484])

On April 17, 2026 Salubris Biotherapeutics, Inc. (SalubrisBio), a clinical-stage biotechnology company dedicated to discovering and developing novel complex biologic therapeutics, reported expansion cohort data from the Phase 1/2 study of JK06, a 5T4-targeted antibody drug conjugate (ADC), in patients with unresectable locally advanced or metastatic cancer, including non-small cell lung cancer (NSCLC) and breast cancer, which is being presented at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026 on April 17-22, 2026 in San Diego, California.

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"JK06 continues to demonstrate encouraging and durable efficacy among heavily pre-treated metastatic solid tumors. Partial responses have now been observed across four different cancers, including NSCLC and breast cancer, at multiple dose levels. These data are complemented by a consistently favorable safety profile, underscoring our belief that JK06 has the potential to be an important new first-in-class ADC that can address the unmet needs of patients with 5T4-expressing cancers," said Sam Murphy, Chief Executive Officer of Salubris Biotherapeutics. "These results provide a robust foundation for further exploration of JK06 in NSCLC and breast cancer and will propel our efforts to interrogate the pan-tumor opportunity. We look forward to progressing this study into the next stages of expansion cohorts, including additional monotherapy cohorts and evaluation of JK06 in multiple combination therapy regimens."

Expansion cohort data presented at AACR (Free AACR Whitepaper) include 112 patients enrolled in Europe with advanced relapsed/refractory solid tumors who were treated with JK06 once every three weeks, including two randomized dose cohorts (3.7 mg/kg, 4.5 mg/kg) in NSCLC and breast cancer and a basket cohort consisting of multiple tumor types known to express 5T4. The data cutoff was March 29, 2026.

Key efficacy findings include:

Among 38 response-evaluable NSCLC patients, 10 attained confirmed PRs (ORR 26%), including three out of seven response-evaluable squamous cell NSCLC patients (ORR 43%), and two of three response-evaluable Epidermal Growth Factor Receptor (EGFR) mutant patients.
Five out of 19 response-evaluable breast cancer patients attained PRs (ORR 26%), including four out of nine hormone receptor-positive (HR+) breast cancer patients (ORR 44%).
Among other tumor types, the first and only response-evaluable gastric cancer patient enrolled attained a partial response (PR, -55%), and one of four response-evaluable cervical cancer patients attained a partial response (PR, -49%).
Among 112 safety-evaluable patients enrolled in expansion cohorts, key safety findings include:

Treatment with JK06 at doses ≤ 5.2 mg/kg was generally well-tolerated with predominantly low grade (Grades 1 and 2) treatment-related adverse events (TRAEs) and manageable toxicities.
All JK06-related AEs of any grade are below 10% frequency overall except for asthenia (11% overall).
Only three total Grade 3 events have been observed to date among the 112 patients (fatigue, gait disturbance, keratitis), and no Grade 4 or 5 events have been observed.
Of the total 153 patients enrolled across all dose levels in dose escalation and expansion, only seven patients have dose-reduced due to a TRAE resulting from JK06.

The Phase 1/2 open-label, dose-escalation and expansion study (NCT06667960) to assess the safety, pharmacokinetics, and preliminary efficacy of JK06 is ongoing.

Details of the AACR (Free AACR Whitepaper) presentation are as follows:

Title: A Phase 1/2 Study of JK06, a 5T4-Targeted Antibody Drug Conjugate (ADC), In Patients with Unresectable Locally Advanced or Metastatic Cancer
Presenter: Omar Saavedra, M.D., Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain
Abstract #: CT250
Session: Phase II Clinical Trials
Date/Time: April 21, 2026 | 2:00 – 5:00 PM PT

About JK06

JK06 is a first-in-class quadrivalent, biparatopic ADC that selectively targets 5T4 with a monomethyl auristatin E (MMAE) payload. 5T4 is an oncofetal protein that is overexpressed in a wide range of solid tumors, including non-small cell lung cancer (NSCLC), breast, gastric and genitourinary cancers, and is associated with more aggressive tumor progression and reduced survival. JK06 has demonstrated picomolar affinity for 5T4 and enhanced internalization resulting from the biparatopic design. Together with stable, site-specific payload conjugation, JK06 has demonstrated the potential for robust efficacy and a favorable safety profile.

(Press release, Salubris Biotherapeutics, APR 17, 2026, View Source [SID1234664500])